He didn't own the original Shakespeare & Co., where Hemingway hung out in the 1920s, because that book store closed in 1941 on account of the Nazis. The original owner was Sylvia Beach, who published James Joyce's "Ulysses" in 1922.

But Whitman bought the stock of books from the original store, and opened it up again after the war.

I don't know if Hemingway ever visited Whitman's store, but William Burroughs, Allen Ginsberg, Henry Miller, and the like went there.